Add this code to the Custom CSS field on the Settings tab of your Blog widget’s settings:
[class*="Popup"] svg {
visibility: hidden;
}
[class*="Popup"] button[class*="PopupClose"] {
background-image: url(https://cdn.pixabay.com/photo/2022/07/24/11/35/women-7341444_1280.jpg);
background-size: contain;
background-repeat: no-repeat;
background-position: center center;
}
Do not forget to replace the image url with the url of your image.
Result:
